A Response to Jim on Tradesports:
Given that Jim hasn't opened comments for his post, I hope VC readers won't mind an up-top response to Jim's post and update below about the usefulness of Tradesports in predicting who Bush would nominate to replace Justice O'Connor.

  Jim describes my earlier post as "incorrect or misleading." But as best I can tell, the only apparent ground for his characterization is that I said Roberts was trading at 1% "about 2 hours" before my post, when the exact time Roberts was trading at 1% was 2 hours and 45 minutes before my post. But even assuming we construe "about" to exclude a 45-minute error window, what difference does that make? It doesn't seem relevant to the usefulness of Tradesports in this context.

  The question I asked in my initial post was whether we expect a site like Tradesports to provide something "particularly useful" on the issue of O'Connor's replacement, or to "just mirror the collective common wisdom of newspapers and blogs." I gather the answer is that Tradesports simply mirrored the common wisdom: its predictions simply reflected what newspapers and blogs were saying, with a built-in time delay of anywhere from a few minutes to an hour. So, for example, K.J. Lopez at The Corner put up a post predicting Roberts at 5:24pm, and about a half hour later, Roberts went from 1% to 10% on Tradesports. I suppose this means that you could try to use Tradesports as a way of monitoring what a few newspapers and blogs are saying, but on the whole this seems like a quite modest function. It seems easier to just scan the headlines at How Appealing.